All polymer clay must be conditioned to some degree before you work with it. To prepare the stiffer clays for conditioning, prewarm them by placing the unopened packages of clay on a heating pad set to low or in a sealed plastic bag in a bowl of warm water.
To condition clay by hand, roll the clay into a ball, flatten it, and roll it into a snake. Fold the snake in half, twist it, and roll it into a ball again (Figure 1). Repeat until the clay is soft and pliable.
Polymer clay can also be conditioned with a pasta machine dedicated to nonfood use. Adjust the machine to its thickest setting, flatten one end of the clay, and run it through the machine (Figure 2). Fold the sheet of clay in half, and run it through the machine again, folded-side first. Use a needle tool to puncture any air pockets that form. Continue to fold the clay (in the same direction each time) and run it through the machine until it’s soft and pliable.